Heat retaining drum for furnaces and the like



E. HIRTER 2,252,631

HEAT RETAINING DRUM FOR FURNACES AND THE LIKE Aug. 12, 1941.

Filed April 25, 1940 2 Sheets- Sheet 1 did I If

A llorney 1941- I E. HIRTER 1 HEAT RETAINING DRUM FOR FURNACES AND THE LIKE Filed April 23, 1940 2 Sheets-Sheet 2 Allorney Patented Aug. 12, 1941 UNITED STATESe PATENT OFFICE y. HEAT RETAINING DRUM FOIt FURNACES i AND LIKE Ernest Hirter, Dundee, Oreg.

Application April 23, 1940, Serial No. 331,221

2 Claims.

The present invention relates to heating plants, such as furnaces, circulating heaters, stoves and the like,iand has for its primary object to provide a heat retaining drum mounted in the combustion chamber of the furnace and adapted to collect and retain a portion of the heated gases within the furnace to more eifectively utilize such heated gases before permitting the same to escape through the smoke stack.

An important object of the present invention is to provide a heat retaining drum of this character which is adjustable to furnaces or stoves of various sizes in order to reduce the number of sizes of the heat retaining drums to be carried in stock for installing in furnaces having combustion chambers of various sizes. a a a A further object is to provide an attachment of this character of simple and practical construction, which is efiicient in performance, relatively inexpensive to manufacture and install in operative position and otherwise well adapted for the purposes for which the same is intended.

Other objects and advantages reside in the details of construction as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming part hereof wherein like numerals refer to like parts throughout, and in which Figure 1 is a vertical sectional view through a conventional type of hot-air furnace showing the heat retaining drum mounted in position therein,

Figure 2 is a transverse sectional view taken substantially on a line 2-2 of Figure 1,

Figure 3 is a fragmentary vertical sectional view showing the cold air intake pipe,

Figure 4 is a group perspective view of the heat retaining drum,

Figure 5 is a similar view of the adjustable ex tension at the lower end of the drum,

Figure 6 is a similar view of the pipe provided for connecting the hot-air chamber of the furnace with the hot-air chamber of the heatin drum, and

Figure 7 is a top plan view of the heat retaining drum.

Referring now to the drawings in detail, the numeral 5 designates a hot-air furnace of conventional construction and which includes the outer shell 6 and the inner shell I to define the hot-air chamber 8 therebetween. The fire-box is shown at 9 for heating the interior of the inner shell I and connected thereto, adjacent its upper portion, is the smoke stack I t.

The top of the inner shell 1 is provided with an opening I I within the edges of which is snugly fitted the heat retaining drum designated gencrally at 12. The heat retaining drum includes a tubular member it having an outturned flange [4 at its upper end which is bolted or otherwise secured to the top of the inner shell 7, as shown at I5.

Arranged vertically in the tubular member I3 is the tubular heat trap I6 having its walls spaced from the member 13, the trap It being open at 3 its bottom and closed at its top and supported at snugly fitted within the lower portion of the tubular member i3. An air chamber 201 is thus formed between the tubular member 13 and the trap l6 which is closed at its bottom and communi cates at its upper end with the hot air chamber 8. The lower portion of the hot air chamber 20 has atmospheric communication by means of a plurality of horizontal pipes 29 extending through the inner shell I and the outer shell 6 and having their end portions welded or otherwise permanently secured to the tubular member l3 and said outer shell. Cold air may be admitted into the chamber 20 by means of a vertically disposed pipe 3 3 having a horizontal upper end 3| inserted into the pipe 29, the lower end of the pipe 30 being open.

Telescoping upwardly over the lower end of the tubular member I3 is a tubular extension 2| adapted for retaining in vertically adjusted position by means of a bolt 22 inserted in the vertically extending slotted opening 23 of the extension and through the opening 24 of the tubular member I3. Slotted openings 2! accommodate the pipes 29. The lower end of the extension 2! tapers inwardly as shown at 25 to provide a reduced opening 26 in its bottom portion. The walls of the tubular member l3 adjacent its lower end as well as the walls of the extension 2! are provided with registering openings 21.

From the foregoing it will be apparent that the heat retaining drum serves to retain a portion of the heat from the combustion chamber of the furnace and thus more effectively utilize the gases for heating the air in the hot air chamber 8 and the hot air chamber 253 before permitting the heated gases to pass through the smoke stack Ill.

When desired the plate 28 on top of the furnace may be removed and a hot air register substituted therefor, or a suitable duct connected to the furnace for conveying the heated air to a desired location.

The extension 2| may be adjusted to suit the particular size of furnace in which the heat retainer is mounted and it will be obvious that the point above the lower edge of the container, said nace. The openings 21 in the sidewalls of the heating drum adjacent the lower end thereof, are provided to produce a better circulation of the heated gases into and out of the drum. It will be apparent that should a high flame rise from the fire bed 9 and enter the lower opening 26 of the drum, that it is necessary to permit the escape of the heated gases from the drum in order not to create back pressure which would tend to smother the flames. Accordingly, the openings 21 accomplish this purpose.

It is pointed out that the openings 21 will not at any time be entirely closed since upon the lowering of the extension 2!, the opening 21 in the extension will be moved below the lower edge of the tubular member [3.

The adjustment of the extension 25 enables the opening 26 at the lower end thereof to be moved toward or away from the fire bed to permit an adjustment thereof in accordance with the size of the furnace and the size of the flame contained therein.

It is believed the details of construction, oper ation and advantages of the device will be understood from the foregoing without further detailed explanation.

Having thus described the invention, what I claim is:

1. An attachment for furnaces and the like comprising a container composed of a pair of telescoping sections, means for suspending the container in the combustion chamber of the furnace, the lowermost of said sections having apertures constituting intake and discharge ports for admitting heated gases into the uppermost section and discharging the same therefrom at a lower section having an inwardly inclined lower edge constituting a deflector for directing heated gases toward the side walls of the furnace, and means for securing the lowermost section in vertically adjusted position relative to the uppermost section.

2. An air heating furnace comprising in combination, an inner shell constituting the combustion chamber and an outer shell spaced therefrom and constituting an air chamber, a tubular member suspended from the top of the inner shell, a tubular trap having a closed top supported concentrically in the member to provide a second air chamber between the walls of the trap and the walls of the member, said last named air chamber being closed at its bottom and open at its top for communication with the interior of the first mentioned air chamber, conduits providing atmospheric communication for said last named air chamber, and a tubular extension adjustably connected on the lower end of said first named member having openings in its walls, said extension having a restricted mouth movable toward and away from the heating agent of the furnace.

ERNEST I-IIRTER. 

